According to prior art, for example as described in U.S. Pat. No. 4,174,011, a subsea oil or gas exploitation device comprises a sea floor template that is lowered to the sea bottom for the purpose of defining a base for further equipment needed, such as a Christmas tree construction for each drill hole and a blow out preventer device.
Typically, the template comprises a plurality of well subsea equipment guides. Normally, such well equipment guides comprise a plurality of posts that stand up from a position adjacent individual drilling holes. From said posts, guiding wires extend to a top side device such as a floating vessel, from which further equipment such as Christmas tree arrangements and BOP devices can be lowered down to their operative position on top of the template, initially guided by the wires and finally by the posts. For this purpose, holes or the like are provided in the equipment in question for reception of said posts.
This kind of wire guideline arrangement has the advantage of permitting relatively rapid and precise guiding of said equipment down to the template, as long as the depth does not become too large. At larger depths, for example more than 800 meters, it will become increasingly difficult to avoid that the wires get twisted into each other due to their movements as a result of underwater streams etc. If the wires get twisted, further guiding by means thereof becomes impossible, something that cannot be tolerated for safety reasons as well as operational and economical reasons.